Slight spoke ping when climbing...

Discussion in 'Cycling Equipment' started by typ993, Apr 12, 2006.

  1. typ993

    typ993 New Member

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    The spokes on my rear wheel (Rolf Vector Pro) have started making a slight pinging sound, but only when climbing, not on level ground. The wheel is true and round to within fractions of a millimeter.

    Is this a cause for concern or is it just a function of the more uneven pedaling forces exerted when climbing? I broke a spoke last year on this wheel, though the noise the spoke made then was much more pronounced. The wheel seemed true then, though.
     
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  2. artmichalek

    artmichalek New Member

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    It sounds like a spoke tension issue. The pinging is the sound of a spoke going slack. Who replaced the spoke when you broke it? I would find a reputable shop that can check your spoke tension against the manufacturer spec.
     
  3. daveornee

    daveornee New Member

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    Rolf Vector Pro rear hubs have crack failure issues.
    Take a close look at the hub looking for cracks. Any fine crack will propogate pinging sounds to the spokes.
     
  4. typ993

    typ993 New Member

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    Thanks, I suspect it may be spoke tension issues, as the spokes vary considerably in tone when plucked. I had the rear hub rebuilt last year when the bearings went out, so I assume the shop would have noticed cracking, but I'll take another look.
     
  5. typ993

    typ993 New Member

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    Here's a followup on this for the benefit of future searchers...

    Once I took the wheel off and plucked the spokes, the tone seemed much more consistent (hence spoke tension was pretty equivalent between all the spokes). The shop confirmed this.

    What the shop did do was put a small drop of lubricant on all the spoke heads on the hub. The mechanic there said that sometimes the spokes could get frozen in place and the stress on the heads could make some noise (and eventually break a spoke).

    Took one ride and still noticed some pinging. From the next ride on, the pinging disappeared, so I guess it took a little time for the lubricant to work its way in and for the spokes to resettle. Problem solved!
     
  6. ryanspeer

    ryanspeer New Member

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    I'm looking into a pair of Vector Pro's right now - this is all good to know for a prospective buyer.

    By the way typ993, where in Edmonds do you live? My wife and I just moved from there up to Lake Stevens last year. I grew up in Edmonds riding my bike all over the place (both mountain and road). Some good training ride routes exist down there - that's for sure!
     
  7. typ993

    typ993 New Member

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    I'm in the Meadowdale area. I use Meadowdale Beach Road and North Meadowdale Beach Road for hill intervals. 20% gradient on the lower part of North Meadowdale! :eek:

    Also, another note on the Vector Pro saga: I'm still getting pinging from time to time, so reapplication of lube might be necessary. Either that, or a spoke is getting loose in the rear somewhere.
     
  8. chris davis

    chris davis New Member

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    i would have thought that the rear mech is clipping the spokes when the wheel flexes under load. just ajust the stops on the rear mech and it will go away.
     
  9. typ993

    typ993 New Member

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    "Rear mech" meaning the rear derailleur? If so, that is not it. The Vector Pro has black spokes and there would be visible rub marks if that were the case. The sound is also not a rubbing sound.
     
  10. chris davis

    chris davis New Member

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    not necessarily, i have had this too and no rubbing marks, with black spokes too.

    it doesn't rub so much as just glances off them every now and then when climbing.
     
  11. ScienceIsCool

    ScienceIsCool New Member

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    When something under tension is going "ping", it's because something is causing motion, kind of like plucking a guitar string. My guess is that there's a problem at the hub. If you look closely, I bet the spoke hole at the hub has some kind of defect that the spoke is slipping into momentarily. Just a guess...

    John Swanson
    www.bikephysics.com


     
  12. ScienceIsCool

    ScienceIsCool New Member

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    Not true. Try plucking a slack rubber band. No noise. Try plucking a taut rubber band. Twang! I doubt the spoke is going completely slack for a number of reasons. As I said above, it's most likely caused by a small movement, such as slipping in and out of a small defect at the hub spoke hole.

    John Swanson
    www.bikephysics.com


     
  13. chris davis

    chris davis New Member

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    one way to test this, put it in the second from biggest on the back and see if it stops.
     
  14. typ993

    typ993 New Member

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    Nope, still pings when in lower cogs. I think it's probably a spoke that has loosened up. Probably just have the shop retension it or rebuild it this winter. That way, they can also check the hub for defects.

    Still can't figure out why the wheel is true and round, though, if a spoke is loose, particularly on these high-tension wheels.
     
  15. ScienceIsCool

    ScienceIsCool New Member

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    It's not a loose spoke. A loose spoke won't cause the noise you described, especially under load. The most likely explanation is a defect (i.e., crack in the material) at the rim or hub. If that is in fact true, then you're looking at an imminent failure. I'd get it looked at right away.

    John Swanson
    www.bikephysics.com


     
  16. rustynuts

    rustynuts New Member

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    It might be that when the wheel had a new spoke fitted and was subsequently re-trued, the mechanic didn't "flex" the wheel ('flexing' the wheel is when the wheel is placed on a hard surface and pressure put on the rim sides. The aim of this is to release spoke wind up). If the wheel isn't flexxed the spoke wind up releases itself under hard pedalling, making pinging noises.
     
  17. typ993

    typ993 New Member

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    That could certainly be.

    Well, this week, the wheel has stopped making noise. Sometimes it does, sometimes it doesn't and I'm riding the same route. I'm at my wit's end on this, but like I said, I might just get it rebuilt this winter.
     
  18. ScienceIsCool

    ScienceIsCool New Member

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    I'm sorry , but that's not quite correct. The idea behind "flexing" the wheel is to stress relieve the spokes at the bend (as they enter the hub) by yielding them a bit. The bend area of the spoke has a large amount of residual stress from the manufacturing process, which can lead to premature fatigue failure if not corrected.

    The ironic part is that the method you describe doesn't stress the spokes past yield, so it doesn't do anything at all. To properly yield them, you need to grab a pair in your hands and give them a really good squeeze, preferably before the wheel has been tensioned and trued.

    I still think the pinging noise is your audible warning that the rim or hub flange is starting to crack. One reason that the noise is disappearing is because the crack is opening up a bit and is that much closer to failure.

    John Swanson
    www.bikephysics.com


     
  19. typ993

    typ993 New Member

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    Maybe, but this is a black anodized hub. I've held it under a bright halogen light and I have not seen any cracks. Cracks should have been visible, unless they are lying only under a spoke and not appearing on the other side.
     
  20. bobbyOCR

    bobbyOCR New Member

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    I had the same issue with a 32-hole 2-cross laced rear wheel. The spokes may be unevenly tensioned. When you are climbing, also out of the saddle, much more power is put through the spokes. If they are crossed, when you accelerate, gravity wants you to go down, while your power wants you to go up so the wheels suffer inertia. The rims don't rotate at the same speed as your hub for a split second, and the spokes can ping as the move together, and in the hub holes, also the nipple in the rim. It isn't anything to be alarmed about and comes as a side effect of having a higher spoke count wheel with less tension in each spoke. Only problem is your mates can hear you as you come up behind them on a climb [​IMG]
     
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